alvinalexander.com | career | drupal | java | mac | mysql | perl | scala | uml | unix  

What this is

This file is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" TM.

Other links

The source code

/*****************************************************************************
 *                                                                           *
 *  This file is part of the BeanShell Java Scripting distribution.          *
 *  Documentation and updates may be found at http://www.beanshell.org/      *
 *                                                                           *
 *  Sun Public License Notice:                                               *
 *                                                                           *
 *  The contents of this file are subject to the Sun Public License Version  *
 *  1.0 (the "License"); you may not use this file except in compliance with *
 *  the License. A copy of the License is available at http://www.sun.com    * 
 *                                                                           *
 *  The Original Code is BeanShell. The Initial Developer of the Original    *
 *  Code is Pat Niemeyer. Portions created by Pat Niemeyer are Copyright     *
 *  (C) 2000.  All Rights Reserved.                                          *
 *                                                                           *
 *  GNU Public License Notice:                                               *
 *                                                                           *
 *  Alternatively, the contents of this file may be used under the terms of  *
 *  the GNU Lesser General Public License (the "LGPL"), in which case the    *
 *  provisions of LGPL are applicable instead of those above. If you wish to *
 *  allow use of your version of this file only under the  terms of the LGPL *
 *  and not to allow others to use your version of this file under the SPL,  *
 *  indicate your decision by deleting the provisions above and replace      *
 *  them with the notice and other provisions required by the LGPL.  If you  *
 *  do not delete the provisions above, a recipient may use your version of  *
 *  this file under either the SPL or the LGPL.                              *
 *                                                                           *
 *  Patrick Niemeyer (pat@pat.net)                                           *
 *  Author of Learning Java, O'Reilly & Associates                           *
 *  http://www.pat.net/~pat/                                                 *
 *                                                                           *
 *****************************************************************************/

package bsh;

class BSHMethodDeclaration extends SimpleNode
{
	public String name;

	// Begin Child node structure evaluated by insureNodesParsed

	BSHReturnType returnTypeNode;
	BSHFormalParameters paramsNode;
	BSHBlock blockNode;
	// index of the first throws clause child node
	int firstThrowsClause;

	// End Child node structure evaluated by insureNodesParsed

	public Modifiers modifiers;

	// Unsafe caching of type here.
	Class returnType;  // null (none), Void.TYPE, or a Class
	int numThrows = 0;

	BSHMethodDeclaration(int id) { super(id); }

	/**
		Set the returnTypeNode, paramsNode, and blockNode based on child
		node structure.  No evaluation is done here.
	*/
	synchronized void insureNodesParsed() 
	{
		if ( paramsNode != null ) // there is always a paramsNode
			return;

		Object firstNode = jjtGetChild(0);
		firstThrowsClause = 1;
		if ( firstNode instanceof BSHReturnType )
		{
			returnTypeNode = (BSHReturnType)firstNode;
			paramsNode = (BSHFormalParameters)jjtGetChild(1);
			if ( jjtGetNumChildren() > 2+numThrows )
				blockNode = (BSHBlock)jjtGetChild(2+numThrows); // skip throws
			++firstThrowsClause;
		}
		else
		{
			paramsNode = (BSHFormalParameters)jjtGetChild(0);
			blockNode = (BSHBlock)jjtGetChild(1+numThrows); // skip throws
		}
	}

	/**
		Evaluate the return type node.
		@return the type or null indicating loosely typed return
	*/
	Class evalReturnType( CallStack callstack, Interpreter interpreter )
		throws EvalError
	{
		insureNodesParsed();
		if ( returnTypeNode != null )
			return returnTypeNode.evalReturnType( callstack, interpreter );
		else 
			return null;
	}

	String getReturnTypeDescriptor( 
		CallStack callstack, Interpreter interpreter, String defaultPackage )
	{
		insureNodesParsed();
		if ( returnTypeNode == null )
			return null;
		else
			return returnTypeNode.getTypeDescriptor( 
				callstack, interpreter, defaultPackage );
	}

	BSHReturnType getReturnTypeNode() {
		insureNodesParsed();
		return returnTypeNode;
	}

	/**
		Evaluate the declaration of the method.  That is, determine the
		structure of the method and install it into the caller's namespace.
	*/
	public Object eval( CallStack callstack, Interpreter interpreter )
		throws EvalError
	{
		returnType = evalReturnType( callstack, interpreter );
		evalNodes( callstack, interpreter );

		// Install an *instance* of this method in the namespace.
		// See notes in BshMethod 

// This is not good...
// need a way to update eval without re-installing...
// so that we can re-eval params, etc. when classloader changes
// look into this

		NameSpace namespace = callstack.top();
		BshMethod bshMethod = new BshMethod( this, namespace, modifiers );
		try {
			namespace.setMethod( name, bshMethod );
		} catch ( UtilEvalError e ) {
			throw e.toEvalError(this,callstack);
		}

		return Primitive.VOID;
	}

	private void evalNodes( CallStack callstack, Interpreter interpreter ) 
		throws EvalError
	{
		insureNodesParsed();
		
		// validate that the throws names are class names
		for(int i=firstThrowsClause; i
... this post is sponsored by my books ...

#1 New Release!

FP Best Seller

 

new blog posts

 

Copyright 1998-2021 Alvin Alexander, alvinalexander.com
All Rights Reserved.

A percentage of advertising revenue from
pages under the /java/jwarehouse URI on this website is
paid back to open source projects.